The present invention relates to a hand held electric ejecting device for ejecting material such as caulking from a cartridge.
Various hand held electric ejecting devices for ejecting materials from a cartridge are known. In such devices the electric motors are positioned to one side or beneath the cartridge and its support. One such prior art device is shown in U.S. Pat. No. 4,180,187. In this prior art device the motor is positioned beneath the cartridge and its support. As a result of this arrangement a relatively complex driving mechanism, one employing gearing or sprockets, a chain drive and a clutch member, is necessary to advance the pusher. The necessity for such a driving mechanism not only renders the device relatively expensive but also increases the weight thereof which adversely affects the ease with which such a device may be used.
An object of the present invention is to provide a hand held electric ejecting device for ejecting material such as caulking from a cartridge which overcomes the aforementioned disadvantages of the prior art devices.
More particularly, an object of the present invention is to provide a hand held electric ejecting device for ejecting material from a cartridge, which is relatively simple in design using a minimum number of parts whereby there results an ejecting device of relatively low cost and weight.
A further object of the present invention is to provide a device of the aforementioned type which is more compact, slimmer, better balanced with respect to the longitudinal axis of the device and hence easier to use than known devices.
This and other objects of the present invention are attained by providing a hand held electric ejecting device for ejecting material from a cartridge comprising in combination, receptacle means for receiving therein a cartridge containing a material to be ejected, said cartridge having a dispensing opening at one end and being adapted to receive a pusher means at the other end for forcing the material in the cartridge through the dispensing opening; pusher means movable when driven through said cartridge from said other end to force the material in the cartridge through said dispensing opening, said pusher means including a push rod; and an electric motor positioned adjacent one end of said receptacle means and connected to said device, said push rod passing through the electric motor and being axially driven thereby for effecting movement of the pusher means to force material through the dispensing opening of the cartridge.
In a disclosed embodiment of the present invention the push rod is a screw shaft which is in longitudinal alignment with the cartridge and extends through the center of the motor. More specifically, the screw shaft passes through an armature shaft of the motor, threads on the armature shaft drivingly engaging the screw shaft thereby translating rotary motion of the armature shaft to axially drive the screw shaft.
A further feature of the present invention involves the provision of means for automatically shutting off the electric motor after the pusher means has been driven a predetermined, adjustable distance. According to the disclosed embodiment of the present invention this automatic shutoff means includes an adjustable stop provided on the push rod and a switch in the form of a plunger pin mounted on the electric motor adjacent to the push rod passing through the motor, the switch being actuated by the stop to shut off the motor after the pusher means has been driven the predetermined, adjustable distance.
A pistol grip is provided on the disclosed device. This grip is connected to the electric motor and has a trigger switch for actuation of the electric motor.
According to the disclosed form of the present invention the receptacle means is in the form of a cylinder for receiving the cartridge. The cylinder is provided with removable end caps. One of these end caps is connected to the motor whereby the motor can be removed for replacement or repair.